MamZ protein plays an essential role in magnetosome maturation process of Magnetospirillum gryphiswaldense MSR-1

Journal of Oceanology and Limnology - Based on analysis of gene structure of mamXY operon in Magnetospirillum gryphiswaldense strain MSR-1, we constructed a mamZ deletion mutant strain (ΔmamZ)...     

Replacement of Dietary Fish Oil with Vegetable Oils Improves the Growth and Flesh Quality of Large Yellow Croaker （Larmichthys crocea）

We investigated the effect of the replacement of dietary fish oil with vegetable oils on the growth and flesh quality of large yellow croaker(Larmichthys crocea). The basal diet(FO) was formulated to contain 66.5% fish meal and 6.4% menhaden fish oil; whereas the other 3 experimental diets were formulated by replacing the fish oil with 50% soybean oil(SO50), 100% soybean oil(SO100) and 100% palm oil(PO100), respectively. The 4 diets were randomly assigned to 4 floating sea cages(3.0 m × 3.0 m × 3.0 m), and each was stocked with 250 fish individuals with an initial average weight of 245.29 g ± 7.45 g. The fish were fed to apparent satiation twice a day at 5:00 and 17:00, respectively, for 12 weeks. Experimental analysis showed that the specific growth rate of fish fed SO50 or PO100 were significantly higher than that of fish fed FO or SO100(P0.05), and crude lipid contents of ventral muscle and viscera were significantly lower in fish fed FO than in those fed the other 3 diets(P0.05). No significant differences in condition factor, viscerosomatic index, hepatosomatic index, gutted yield and colorimetric values of fish among the dietary treatments were observed(P0.05). Compared to FO diet, SO50, SO100 and PO100 diets led to substantial decreases in the liquid loss and water loss from fresh fillets(1 d, 4℃)(P0.05). Similarly, thiobarbituric acid reactive substance(TBARS) values of fillets under different storage conditions(1 d, 4℃; 7 d, 4℃; 4 weeks,-20℃; 8 weeks,-20℃) decreased significantly after partial or complete replacement of fish oil with vegetable oils. These findings indicated that the growth performance and selected flesh quality properties(liquid holding capacity and TBARS value) of large yellow croaker were substantially improved by replacing dietary fish oil with vegetable oils.     

Changes in Land Use and Agricultural Production Structure Before and After the Implementation of Grain for Green Program in Western China–Taking Two Typical Counties as Examples

Soil erosion becomes a serious environmental problem in the world, especially in western China. An effective management practice called the Grain for Green Program （GGP）, which was launched in 1999, aims to reduce soil and water loss and alleviate the ecological environment problem in western China. Two typical counties in western China, the Zhongxian （in Chongqing Municipality） and Ansai （in Shaanxi Province） were chosen to evaluate the dynamic changes of land use and agricultural production structure before and after the implementation of the Program in this paper. The results showed that the cultivated land area was reduced by 7.08% from 1989 to 2003. The cultivated land per person was decreased by 8.42% during 1999-2003. Moreover, the stability index of the secondary sector of the economy was increased from 0.91 in the period 1990-1999 to 0.94 in the following ten years. In addition, the stability index of tertiary economic sector increased from 0.88 to 0.92 in Zhongxian county. Meanwhile, the cultivated land area was reduced by 15.48% from 1990 to 1999. The soil erosion modulus was decreased by 33.33% from 1999 to 2006. Also, the stability index of secondary and tertiary economic sectors was 0.86 in the period 1998-2002. However, it decreased by 77% during 2002 to 2007 in Ansai County. These results imply that the Grain for Green Program had different impact on the two regions. Several effective strategies of soil and water conservation have been carried out to ameliorate the sustainable development of ecological environment and economy in these two counties of western China.     

Fine root distribution pattern of different aged Leucaena leucocephala trees in debris flow source area in Jiangjia Gully,China

Fine root is critical to restrain soil erosion and its distribution pattern is of great influence on the restraining effects. This study studied the fine root biomass(Br) distribution of different aged Leucaena leucocephala(5, 10, 15 years) in debris flow source area in Jiangjia Gully by digging downward to the bottom at different distances to stem in three directions on slope. The results showed the Br increased dramatically by 143% from 5 years to 10 years and then rose slowly by 38% from 10 years to 15 years. The Br of 5 years was significantly asymmetric between uphill and alonghill directions, but there was little difference among directions for other ages, and a concentration trend appeared to exist in downhill and alonghill directions. Moreover, fine root(D≤1 mm) was significantly heavier than that of fine root(1mmD≤2 mm), playing a leading role in the vertical distribution of the whole fine root, with a logarithmic or an exponential function. The results presented may shed light on fine root distribution pattern and evaluation of its effect on slope stability in debris flow source area.     

山东省聊城市矿业权设置方案简述

该文对聊城市自然地理、地质特征进行了概述,对聊城市矿产资源的现状及基本特点、矿业权设置现状进行了总结,在此基础上进行了矿业权区块的划分,完成了聊城市矿业权的设置工作,提出了方案实施的保障措施。     

Linking Tarim Basin sea retreat (west China) and Asian aridification in the late Eocene

The Tarim Basin in western China formed the easternmost margin of a shallow epicontinental sea that extended across Eurasia and was well connected to the western Tethys during the Paleogene. Climate modelling studies suggest that the westward retreat of this sea from Central Asia may have been as important as the Tibetan Plateau uplift in forcing aridification and monsoon intensification in the Asian continental interior due to the redistribution of the land‐sea thermal contrast. However, testing of this hypothesis is hindered by poor constraints on the timing and precise palaeogeographic dynamics of the retreat. Here, we present an improved integrated bio‐ and magnetostratigraphic chronological framework of the previously studied marine to continental transition in the southwest Tarim Basin along the Pamir and West Kunlun Shan, allowing us to better constrain its timing, cause and palaeoenvironmental impact. The sea retreat is assigned a latest Lutetian–earliest Bartonian age (ca. 41 Ma; correlation of the last marine sediments to calcareous nannofossil Zone CP14 and correlation of the first continental red beds to the base of magnetochron C18r). Higher up in the continental deposits, a major hiatus includes the Eocene–Oligocene transition (ca. 34 Ma). This suggests the Tarim Basin was hydrologically connected to the Tethyan marine Realm until at least the earliest Oligocene and had not yet been closed by uplift of the Pamir–Kunlun orogenic system. The westward sea retreat at ca. 41 Ma and the disconformity at the Eocene–Oligocene transition are both time‐equivalent with reported Asian aridification steps, suggesting that, consistent with climate modelling results, the sea acted as an important moisture source for the Asian continental interior.     

2001-2010年中国区域旅游效率评估

选择旅游酒店数、旅行社数、旅游酒店从业人员数和旅行社从业人员数为旅游投入因素,旅游总收入为产出变量,运用数据包络分析方法中的 C2 R 模型分析2001-2010年中国区域旅游效率及其空间格局和变化趋势。中国四大区域的平均旅游效率由高至低依次为东部地区、东北地区、中部地区和西部地区。在31个中国大陆省级行政区中,天津在2001-2010年期间每年都为旅游效率最高的省份。从时间的角度,中国区域旅游效率经历了一个波浪式变化过程,2003年和2008年是2个明显的波谷。2001-2005年四大区域旅游效率的变化过程基本一致。2005-2010年四大区域旅游效率变化各不相同,东部地区呈逐步下降趋势,中部地区先增长、2010年开始下降,西部地区为起伏不定,东北地区为持续增长。     

环渤海地区中心城市金融竞争力评价及辐射研究

以环渤海地区中心城市为研究区域,通过建立城市金融竞争力评价指标体系,运用突变级数法、主成分分析法、层次分析法对环渤海地区中心城市金融竞争力进行综合评价,并通过威尔逊模型揭示了中心城市的辐射范围。环渤海地区中心城市金融发展不平衡,北京的城市金融竞争力遥遥领先于其他城市;环渤海地区并未形成一个紧密联系的金融辐射网络,金融一体化还不成熟,仍有金融盲区的存在;各中心城市在发挥自身优势的同时应打破地区间行政壁垒,优势互补,协同发展,带动环渤海地区金融发展。     

芜湖高铁建设对居民出游行为影响调查及对策研究

从居民旅游交通决策行为、居民出游空间、居民出游行为预期影响3个角度分析芜湖市高铁建设对城市居民出游的影响.结果表明：（1）旅游交通是影响居民旅游决策的重要因素.（2）居民出游市场以近程为主,空间分布主要集中在100-400 km范围内,且东向出游特征明显,目的地以长三角地区为主.（3）高速铁路开通将增加芜湖居民出游交通工具的选择,改变原有的旅游市场空间,中远程出游比例增加,同时也会影响居民出游次数与天数以及景区的选择.最后,依据国内外学者对高铁旅游研究成果,结合本次问卷调查实际情况,初步探讨高速化背景下,芜湖市旅游的发展对策.     

基于GPS反射信号的岸基海冰探测的研究

本文论述了全球导航卫星系统反射信号测量（GNSS-R）在海冰介电常数和海冰密集程度方面的潜在的研究价值,对欧洲空间局在格林兰岛迪斯科海岸采集的海冰数据进行分析,处理了两种反射信号的幅度的量化关系,同时跟踪多颗GNSS卫星并且保证了数据处理时间的连续性和有效性。根据双极化反射信号的幅度极化比和模拟海冰表面复介电常数得出结论, 幅度极化比和海冰表面的介电常数变化有联系。